Images that are used for medical purposes are created by medical imaging devices such as X-ray machines, X-ray computer tomography (CT) machines or magnetic resonance imaging (MRI) machines in the image diagnostic facilities of medical institutions. The images are used by diagnostic specialists, in the course of diagnostic image analysis, who use image-processing systems to manipulate and interpret the medical images. The results of a diagnosis of such images are described in image diagnosis reports that are sent to departments that request these reports.
Conventional systems make it possible to capture unprocessed digital images on image servers so that image examinations can be distributed to image display devices via a network on demand, and then introduced into a PACS (picture archiving and communication system) for storage and retrieval of the images.
In the past, the results of a diagnosis of the images were manually copied into an image diagnostic report and the report was then distributed to requesting departments. The image information forming the basis of the image diagnosis was furnished to requesting departments by the diagnostician in the form of a handwritten sketch called a schema as a part of the written report.
More recently, hospital information systems have used word processors to create and transmit image diagnosis reports both for archiving purposes and for distribution to departments that request the reports. The image diagnosis reports are stored in an electronic file and they are either sent to a terminal computer at the requesting department, or transmitted with e-mail. In order to reduce the amount of data transmitted and stored throughout a network, the image data forming the basis of the image diagnosis is scaled down to reduce the size and the resolution of the images before it is transmitted to requesting departments. Therefore, the reports contain much less diagnostic image information than the original images.
For example, a single two-dimensional imaging examination with a CT scanner may produce several hundred pages of image data, each page having 512×512 pixels with a pixel depth of 16 bits. However, the image diagnosis report may have only 1 or 2 pages of images with a resolution of 256×256 pixels and a pixel depth of only 8 bits.
The advent of three-dimensional imaging and four-dimensional imaging (three spatial dimensions plus time) technology has exacerbated the problem because the image files are much larger than 2D files. Moreover, it is more important to maintain the resolution of the 3D and 4D files because they are used in ways that require great precision, such as design and control of surgical procedures and the fabrication of prosthetics and implants for plastic surgery. One advantage of 3D and 4D images in a diagnostic setting is that they can be manipulated and viewed from different angles. While it is relatively easy to create and manipulate these images in imaging departments having specialized equipment, it is difficult to create and reproduce the images in the using departments, because very large amounts of data must be transmitted through the user network. In many cases, the network that connects the user community (e.g., doctors, wards, operating theatres, etc.) to the imaging department is a narrow bandwidth network that cannot support the required data rates in real time. Furthermore, information flow and control is typically only one way. That is, the image diagnostic reports are created and distributed to using departments, but users cannot modify the images or interactively access additional information. In a large medical facility, there my be hundreds or even thousands of terminals connected to the user network, so it is not feasible to upgrade the network and terminals for high-speed operation.
FIG. 1 is a block diagram illustrating a conventional system of a network environment of image diagnosis devices for an image diagnosis department and requesting departments. An X-ray CT scanner 101, which is one example of an imaging device, creates unprocessed 2D image data which is stored on a PACS server 102. Image display workstations 121 receive stored image data from the PACS server via network 111. The workstations 121 are optimized for processing the 2D images created by the imaging device 101, and produce enhanced 2D images as well as 3D and 4D images which are stored on the PACS server. The network 111 is a large-capacity, high-speed network. Diagnostic specialists perform medical diagnoses at the workstations 121 by processing the image data received from the PACS server 102.
Diagnostic report stations 131 are used by the diagnostic specialists to create image diagnosis reports. An image diagnosis specialist observes two-dimensional images by using image display workstations 121, creates and observes diagnostic images, and creates image diagnosis reports based on the findings obtained in this manner. The diagnostic images, which are very large data files, are stored on the PACS server. As previously mentioned, the network connecting the image diagnosis department with the requesting departments typically has a narrow bandwidth, so the diagnostic images which are attached to the reports are low resolution versions of the images stored on the PACS server.
A hospital information system (HIS) server 141 archives the diagnostic reports and attached low resolution images, and distributes the reports and images to requesting departments. A network 151 is used to distribute reports to user terminals 161 in the requesting departments from the HIS server 141. The users in the requesting departments use the user terminals 161 to view the image diagnosis reports and observe the low-resolution images attached to these reports.
As a result, the value of the diagnostic reports is reduced because the low-resolution images attached to the diagnostic reports provide much less information than the original high-resolution images. At the same time, the high-resolution images consume a large amount of storage space on the PACS server. Therefore, it is desirable to have a system that is capable of providing medical diagnostic reports with high-resolution diagnostic images, to users on low bandwidth networks. It is also desirable to have a system that is capable of providing such high-resolution images without consuming such large amounts of storage space on the image server.